A serious hamstring injury combined with a string of below-par performances saw the midfielder lose his early season confidence, but team-mate Mertesacker believes his compatriot will come good at Wembley.

"I knew before he would suffer at some moment in his first Premier League season," Mertesacker said. "We are happy he is fit again and that he has got a few games under his belt to go now to Wembley and show everything he can do.

"He is one of the best players in Europe and his contribution and his assists are vital for any club. In our cup final at Bremen, he scored the winner, and he is up for the big games."

The turning point for Ozil's season came when he missed a crucial penalty in Arsenal Champions League second round first leg clash to Bayern Munich.

Mertesacker, who berated Ozil for not applauding Arsenal's travelling fans after their 6-3 defeat at Manchester City in December, revealed his team-mates had encouraged the 25-year-old following his miss against Bayern in February.

"We tried to talk to him every day afterwards," Mertesacker said. "I think it is very important to keep his confidence high because sometimes you go through that moment when you suffer a bit and you feel low. I think we've got a good squad to encourage, especially the Germans, of course."